Engines including diesel engines, gasoline engines, natural gas engines, and other engines in the art, may exhaust air pollutants. The air pollutants may be composed of gaseous and solid materials, which include particulate matter. Particulate matter may include unburned carbon particles called soot. In addition, particulate matter may also contain ash, which can be used in engine oils to reduce the acidity of the oil.
The particulate matter generated may be filtered from an exhaust stream. Various technologies may be used to filter particulate matter from an exhaust stream. One of these technologies includes the use of an exhaust element, such as a particulate filter. Particulate filters trap particles contained in the exhaust stream, so the exhaust stream is cleaner when it enters the air as compared to when it exited from the engine. There exist various types of particulate filters in the art. Some filters may include porous filter material or, alternatively, some filters may use wire meshes. The pores or the wire meshes may trap the particulate mater in the exhaust stream as the exhaust stream flows from the input to the output of the filter.
Particulate matter trapped by the filter may eventually clog the filter and reduce the operating efficiency of the engine. As the filter gets clogged, the back pressure to the engine increases. Therefore, the engine may consume more fuel to produce the same amount of power as compared to when the filter is not clogged.
These and other problems may be avoided by periodic cleaning of the filter. Various methods of cleaning filters exist in the art. One method of cleaning the filter is to heat the particulate matter to a temperature at which it combusts or vaporizes. This type of filter cleaning may also be termed as regeneration.
Various regeneration systems have been proposed to regenerate an exhaust element. Many of these systems involve raising the temperature in the exhaust element to aid in regeneration. For example, U.S. Pat. No. 6,422,001 to Sherman et al (“the '001 patent”), which issued on Jul. 23, 2002, describes a method to regenerate particulate filters by adjusting the engine parameters to increase the exhaust temperature. In this method, when the back pressure in the filter reaches a predetermined threshold, the engine speed is decreased and load on the engine is increased. This causes the temperature of the exhaust stream emanating from the engine to increase and, in response, the temperature of the filter may increase. This increase in the filter temperature purportedly aids in regenerating the filter.
While the method of the '001 patent may be used to regenerate an exhaust system element, the method has several shortcomings. The system may be unable to regenerate an exhaust element efficiently because, at times, there may not be sufficient power available for efficient regeneration. Additionally, the system may be unable to regenerate at a time when regeneration is needed because there may not be adequate power available for regeneration. Additionally, the system lacks a capability to calculate the amount of power required to regenerate the exhaust element, to determine how much power is already available for regeneration, or to generate any additional power needed for an efficient regeneration of the exhaust element.
The present disclosure is directed to overcoming one or more of the problems associated with the prior art regeneration method.